Synthesis of a novel series of L-isoserine derivatives as aminopeptidase N inhibitors

A series of novel L-isoserine derivatives were synthesised and evaluated for their ability to inhibit aminopeptidase N (APN)/CD13. In our preliminary biological results, some of these compounds possessed a potent inhibitory activity against the APN. Within this series, compound 14b not only showed similar enzyme inhibition (IC₅₀ of 12.2?μM) compared with the positive control bestatin (half maximal inhibitory concentration (IC₅₀) of 7.3?μM), but also had a potent antiproliferative activity against human cancer cell lines cells.